The present invention relates to a novel ink composition useful in tagging articles for subsequent identification. More particularly, the ink composition contains a fluorescent dye. The present invention also relates to a method of tagging articles using such a composition.
Fluorescent dyes have been used in printing for many different purposes. Among the most prominent uses is as a component in the ink for detecting an attempted fraud or for identifying an article as an original and not a counterfeit. The manner in which the fluorescent component is used to identify an article, or for security purposes in general, can vary greatly.
For example, U.S. Pat. No. 4,889,365 discloses a counterfeit resistant label for goods which is manufactured by printing a code word on the label using an ink, such as a conventional ultraviolet light sensitive ink, that is sensitive to light in the nonvisible spectrum. Japanese Patent Publication 0013799 also discloses a composition comprising colored ink containing a fluorescent material which becomes visible upon UV irradiation. In the use of either of the foregoing compositions, the ink does not have to be abraded off in order to view the fluorescent material under UV radiation.
U.S. Pat. No. 4,451,530 relates to security papers having luminescing authenticity features worked into them or printed on them. The authenticity features used involve a luminophore and one or more absorbing materials by which the emission and/or excitation spectrum of the luminophore is changed in a detectable fashion. The authenticity of the document can then be checked by observing the changed emission or excitation spectrum.
U.S. Pat. No. 4,891,505 discloses a fiduciary document chelate comprising print which is odorless and undetectable in natural or artificial light, but which fluoresces in the red spectrum when excited by UV light. Moreover, the chelate comprising print will fluoresce in the green spectrum when cooled to the temperature of liquid nitrogen. In essence, the fluorescence wavelength of the chelate comprising print is a function of temperature. U.S. Pat. No. 4,736,425 also discloses the use of a chelate in detecting and identifying a fiduciary document as an original. In the first step, one or more elements needed in forming the chelate is or are deposited on the security paper, either at the head of the papermaking machine or during the coating, or at any other stage during its manufacture or finishing. The deposit of the chelate forming element or elements does not alter the color of the paper and does not exhibit any fluorescence. When identification of the document is desired, the missing elements of the chelate is applied to the paper to synthesize the chelate. The chelate synthesized in this manner is an identification mark which is invisible in sunlight or under artificial light, but is visible owing to its fluorescent emission under excitation by ultraviolet light irradiation.
U.S. Pat. No. 3,886,083 discloses a safety ink comprising a UV fluorescent pigment. Upon alteration due to attempted eradication a change in intensity of the fluorescence becomes observable.
Additional patent publications which disclose printed matter comprising UV detectible fluorescent elements include U.S. Pat. Nos. 4,627,642 and 4,500,116. In general, other patent references which disclose fluorescent dye comprising inks include U.S. Pat. Nos. 4,243,694, 4,150,997, 4,186,020 and 4,153,593.
While many different fluorescent ink compositions and methods of using same are available for identification and security purposes, problems can still arise when a commercial black ink is to be employed in the printed matter. Such black ink does not fluoresce and will mask the fluorescence of any fluorescent component contained within the black ink. It would therefore be of a great advantage to the technology to provide a black ink composition which can be used successfully for identification and/or security purposes.
Accordingly, it is an object of the present invention to provide a novel ink composition containing a fluorescent component.
It is another object of the present invention to provide a black ink composition containing a fluorescent component, which ink composition can successfully be used for subsequent identification of tagged articles and/or for security purposes.
Still another object of the present invention is to provide an article which is tagged with such an ink composition such that subsequent identification and/or confirmation of the article is possible.
Still another object of the present invention is to provide a method of tagging articles with the novel ink composition of the present invention.
These and other objects of the present invention will become apparent upon a review of the following specification and claims appended thereto.